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Molecular Probe
A molecular probe is a group of atoms or molecules used in molecular biology or chemistry to study the properties of other molecules or structures. If some measurable property of the molecular probe used changes when it interacts with the analyte (such as a change in absorbance), the interactions between the probe and the analyte can be studied. This makes it possible to indirectly study the properties of compounds and structures which may be hard to study directly. The choice of molecular probe will depend on which compound or structure is being studied as well as on what property is of interest. Radioactive DNA or RNA sequences are used in molecular genetics to detect the presence of a complementary sequence by molecular hybridization. Common probes * Digoxigenin * ANS * Porphyrin * BODIPY * Cyanine * Hybridization probe In molecular biology, a hybridization probe (HP) is a fragment of DNA or RNA, usually 15–10000 nucleotides long, which can be radioactively or f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blotting Compass For Molecular Probes
In molecular biology and genetics, a blot is a method of transferring large biomolecules (proteins, DNA or RNA) onto a carrier, such as a membrane composed of nitrocellulose, polyvinylidene fluoride or nylon. In many instances, this is done after a gel electrophoresis, transferring the molecules from the gel onto the Blotting matrix, blotting membrane, and other times adding the samples directly onto the membrane. After the blotting, the transferred molecules are then visualized by colorant staining (for example, silver staining of proteins), autoradiographic visualization of radioactive tracer, radiolabelled molecules (performed before the blot), or specific labelling of some proteins or nucleic acids. The latter is done with antibody, antibodies or hybridization probes that bind only to some molecules of the blot and have an enzyme joined to them. After proper washing, this enzymatic activity (and so, the molecules found in the blot) is visualized by incubation with a proper reag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleic Acid Hybridization
In molecular biology, hybridization (or hybridisation) is a phenomenon in which single-stranded deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) molecules anneal to complementary DNA or RNA. Though a double-stranded DNA sequence is generally stable under physiological conditions, changing these conditions in the laboratory (generally by raising the surrounding temperature) will cause the molecules to separate into single strands. These strands are complementary to each other but may also be complementary to other sequences present in their surroundings. Lowering the surrounding temperature allows the single-stranded molecules to anneal or “hybridize” to each other. DNA replication and transcription of DNA into RNA both rely upon nucleotide hybridization, as do molecular biology techniques including Southern blots and Northern blots, the polymerase chain reaction (PCR), and most approaches to DNA sequencing. Applications Hybridization is a basic property of nucleotide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybridization Probe
In molecular biology, a hybridization probe (HP) is a fragment of DNA or RNA, usually 15–10000 nucleotides long, which can be radioactively or fluorescently labeled. HPs can be used to detect the presence of nucleotide sequences in analyzed RNA or DNA that are complementary to the sequence in the probe. The labeled probe is first denatured (by heating or under alkaline conditions such as exposure to sodium hydroxide) into single stranded DNA (ssDNA) and then hybridized to the target ssDNA ( Southern blotting) or RNA ( northern blotting) immobilized on a membrane or '' in situ''. To detect hybridization of the probe to its target sequence, the probe is tagged (or "labeled") with a molecular marker of either radioactive or (more recently) fluorescent molecules. Commonly used markers are 32P (a radioactive isotope of phosphorus incorporated into the phosphodiester bond in the probe DNA), digoxigenin, a non-radioactive, antibody-based marker, biotin or fluorescein. DNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyanine
Cyanines, also referred to as tetramethylindo(di)-carbocyanines are a synthetic dye family belonging to the polymethine group. Although the name derives etymologically from terms for shades of blue, the cyanine family covers the electromagnetic spectrum from infrared, near IR to ultraviolet, UV. Chemically, cyanines are a Conjugated system, conjugated system between two nitrogen atoms; in each resonance structure, exactly one nitrogen atom is oxidized to an iminium. Typically, they form part of a nitrogenous heterocycle, heterocyclic system. The main application for cyanine dyes is in Fluorescence microscopy, biological labeling. Nevertheless, there is a wide literature on both their synthesis and uses, and cyanines are common in some CD and DVD media. Structure Cyanines have been classified in many ways: * ''Streptocyanines'' or ''open chain cyanines'': : R2N+=CH[CH=CH]''n''-NR2 (I) * ''Hemicyanines'': : Aryl=N+=CH[CH=CH]''n''-NR2 (II) * ''Closed chain cyanines'': :Ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BODIPY
BODIPY is the technical common name of a chemical compound with formula , whose molecule consists of a boron difluoride group joined to a dipyrromethene group ; specifically, the compound 4,4-difluoro-4-bora-3a,4a-diaza-''s''-indacene in the IUPAC nomenclature. The common name is an abbreviation for "boron-dipyrromethene". It is a red crystalline solid, stable at ambient temperature, soluble in methanol. The compound itself was isolated only in 2009, but many derivatives—formally obtained by replacing one or more hydrogen atoms by other functional groups—have been known since 1968, and comprise the important class of BODIPY dyes.Alfred Treibs und Franz-Heinrich Kreuzer. Difluorboryl-Komplexe von Di- und Tripyrrylmethenen. Justus Liebigs Annalen der Chemie 1968, 718 (1): 208-223. doi: 10.1002/jlac.19687180119 These organoboron compounds have attracted much interest as fluorescent dyes and markers in biological research. Structure In its crystalline solid form, the core ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porphyrin
Porphyrins ( ) are heterocyclic, macrocyclic, organic compounds, composed of four modified pyrrole subunits interconnected at their α carbon atoms via methine bridges (). In vertebrates, an essential member of the porphyrin group is heme, which is a component of hemoproteins, whose functions include carrying oxygen in the bloodstream. In plants, an essential porphyrin derivative is chlorophyll, which is involved in light harvesting and electron transfer in photosynthesis. The parent of porphyrins is porphine, a rare chemical compound of exclusively theoretical interest. Substituted porphines are called porphyrins. With a total of 26 π-electrons the porphyrin ring structure is a coordinated aromatic system. One result of the large conjugated system is that porphyrins absorb strongly in the visible region of the electromagnetic spectrum, i.e. they are deeply colored. The name "porphyrin" derives . Structure Porphyrin complexes consist of a square planar MN4 core. The p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8-Anilino-1-naphthalenesulfonic Acid
8-Anilinonaphthalene-1-sulfonic acid (ANS), also called 1-anilino-8-naphthalenesulfonate, is an organic compound containing both a sulfonic acid and an amine group. This compound is used as a fluorescent molecular probe. For example, ANS can be used to study conformational changes induced by ligand binding in proteins, as ANS's fluorescent properties will change as it binds to hydrophobic regions on the protein surface. Comparison of the fluorescence in the presence and absence of a particular ligand can thus give information about how the binding of the ligand changes the surface of the protein. Its permeability to mitochondrial A mitochondrion () is an organelle found in the cells of most eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used ... membranes makes it particularly useful. References Naphthalenesulfonic acids Fluorescent dyes An ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digoxigenin
Digoxigenin (DIG) is a steroid found exclusively in the flowers and leaves of the plants ''Digitalis purpurea'', ''Digitalis orientalis'' and ''Digitalis lanata'' (foxgloves), where it is attached to sugars, to form the glycosides (e.g. digoxin, lanatoside C). Uses in biotechnology Digoxigenin is a hapten, a small molecule with high antigenicity, that is used in many molecular biology applications similarly to other popular haptens such as 2,4-Dinitrophenol, biotin, and fluorescein. Typically, digoxigenin is introduced chemically (conjugation) into biomolecules (proteins, nucleic acids) to be detected in further assays. Kd of the digoxigenin-antibody interaction has been estimated at ~12 nM (compare to Kd~0.1pM for the biotin-streptavidin interaction). ;DIG-binding proteins Tinberg et al. designed artificial proteins that bind DIG. Their best binder, DIG10.3, was a 141 amino acid protein that bound DIG with a dissociation constant (Kd) of 541 (+/- 193) pM. Anti-digoxi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complementarity (molecular Biology)
In molecular biology, complementarity describes a relationship between two structures each following the lock-and-key principle. In nature complementarity is the base principle of DNA replication and transcription as it is a property shared between two DNA or RNA sequences, such that when they are aligned antiparallel to each other, the nucleotide bases at each position in the sequences will be complementary, much like looking in the mirror and seeing the reverse of things. This complementary base pairing allows cells to copy information from one generation to another and even find and repair damage to the information stored in the sequences. The degree of complementarity between two nucleic acid strands may vary, from complete complementarity (each nucleotide is across from its opposite) to no complementarity (each nucleotide is not across from its opposite) and determines the stability of the sequences to be together. Furthermore, various DNA repair functions as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atoms
Atoms are the basic particles of the chemical elements. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other by the number of protons that are in their atoms. For example, any atom that contains 11 protons is sodium, and any atom that contains 29 protons is copper. Atoms with the same number of protons but a different number of neutrons are called isotopes of the same element. Atoms are extremely small, typically around 100 picometers across. A human hair is about a million carbon atoms wide. Atoms are smaller than the shortest wavelength of visible light, which means humans cannot see atoms with conventional microscopes. They are so small that accurately predicting their behavior using classical physics is not possible due to quantum effects. More than 99.94% of an atom's mass is in the nucleus. Protons have a positive electric charge a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Genetics
Molecular genetics is a branch of biology that addresses how differences in the structures or expression of DNA molecules manifests as variation among organisms. Molecular genetics often applies an "investigative approach" to determine the structure and/or function of genes in an organism's genome using genetic screens. The field of study is based on the merging of several sub-fields in biology: classical Mendelian inheritance, cellular biology, molecular biology, biochemistry, and biotechnology. It integrates these disciplines to explore things like genetic inheritance, gene regulation and expression, and the molecular mechanism behind various life processes. A key goal of molecular genetics is to identify and study genetic mutations. Researchers search for mutations in a gene or induce mutations in a gene to link a gene sequence to a specific phenotype. Therefore molecular genetics is a powerful methodology for linking mutations to genetic conditions that may aid th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Absorbance
Absorbance is defined as "the logarithm of the ratio of incident to transmitted radiant power through a sample (excluding the effects on cell walls)". Alternatively, for samples which scatter light, absorbance may be defined as "the negative logarithm of one minus absorptance, as measured on a uniform sample". The term is used in many technical areas to quantify the results of an experimental measurement. While the term has its origin in quantifying the absorption of light, it is often entangled with quantification of light which is "lost" to a detector system through other mechanisms. What these uses of the term tend to have in common is that they refer to a logarithm of the ratio of a quantity of light incident on a sample or material to that which is detected after the light has interacted with the sample. The term absorption refers to the physical process of absorbing light, while absorbance does not always measure only absorption; it may measure attenuation (of transmitted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
